Perhaps you should try some spelling variations:
giai nghien » giai nghiep, giai nghia, thai nghien
trai nghiem » trac nghiem, thi nghiem
gay nghien » bay nghien, va nghien, tam nghien
khach trai » khac trai, khanh tra, kham trai
nghiem ban » nghiem van, nghiem xuan, nghiep bang
cuu thuoc » cua thuoc, cuu thuc, cay thuoc
te khach » he khach, tri khach, tan khach
te sach » toc sach
ban hoc » bang hoc, van hoc, bai hoc

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach ((giai nghien) OR (gay nghien)) cuu thuoc ) or ( te khach trai nghiem ban hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach ((giai nghien) OR (gay nghien)) cuu thuoc ) OR ( te khach trai nghiem ban hoc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( te sach ((giai nghien) OR (gay nghien)) cuu thuoc ) or ( te khach trai nghiem ban hoc ))".
• Adding a wildcard symbol may retrieve word variants: (( te sach ((giai nghien) OR (gay nghien)) cuu thuoc ) or ( te khach trai nghiem ban hoc ))*.